MATHEMATICAL SYMBOLS
=
Equal sign: equality
≠
Not equal sign: inequality
≈
Approximately equal: approximation
>
Strict inequality: greater than
<
Strict inequality: less than
≥
Inequality: greater than or equal to
≤
Inequality: less than or equal to
<<
Inequality: much less than
>>
Inequality: much greater than
( )
Parentheses: calculate expression inside first
[ ]
Brackets: calculate expression inside first
+
Plus sign: addition
−
Minus sign: subtraction
±
Plus / minus: both plus and minus operations
*
Asterisk: multiplication
×
Times sign: multiplication
⋅
Multiplication dot: multiplication
÷
Division sign / obelus: division
/
Division slash: division
—
Horizontal line: division / fraction
mod
Modulo: remainder calculation
.
Period: decimal point / decimal separator
ab
Power: exponent
a^b
Caret: exponent
√a
Square root: √a ⋅ √a = a
3√a
Cube root: 3√a ⋅ 3√a ⋅ 3√a = a
4√a
Fourth root: 4√a ⋅ 4√a ⋅ 4√a ⋅ 4√a = a
n√a
N-th root (radical)
%
Percent: 1% = 1/100
‰
Per-mille: 1‰ = 1/1000 = 0.1%
ppm
Per-million: 1ppm = 1/1000000
ppb
Per-billion: 1ppb = 1/1000000000
ppt
Per-trillion: 1ppt = 10^-12
GEOMETRY SYMBOLS
∠
Angle: formed by two rays
∟
Right angle: 90°
°
Degree: 1 turn = 360°
deg
Degree: 1 turn = 360deg
′
Prime: arcminute, 1° = 60′
″
Double prime: arcsecond, 1′ = 60″
AB
Line segment: line from point A to point B
⊥
Perpendicular: perpendicular lines (90° angle)
∥
Parallel: parallel lines
≅
Congruent to: equivalence of geometric shapes and size
~
Similarity: same shapes, not same size
Δ
Triangle: triangle shape
|x-y|
Distance: distance between points x and y
π
Pi constant: π = 3.141592654... is the ratio between the circumference and diameter of a circle
rad
Radians: radians angle unit
c
Radians: radians angle unit
grad
Gradians / gons: grads angle unit
g
Gradians / gons: grads angle unit
ALGEBRA SYMBOLS
x
Variable x: unknown value to find
≡
Equivalence: identical to
≜
Equal by definition
:=
Equal by definition
~
Approximately equal: weak approximation
∝
Proportional to
∞
Lemniscate: infinity symbol
≪
Much less than
≫
Much greater than
{ }
Braces: set
⌊x⌋
Floor brackets: rounds number to lower integer
⌈x⌉
Ceiling brackets: rounds number to upper integer
x!
Exclamation mark: factorial
|x|
Vertical bars: absolute value or modulus
f(x)
Function of x: maps values of x to f(x)
(f∘g)
Function composition: (f∘g) (x) = f(g(x))
(a,b)
Open interval: (a,b) = {x | a < x < b}
[a,b]
Closed interval: [a,b] = {x | a ≤ x ≤ b}
∆
Delta: change / difference
∆
Discriminant: Δ = b2-4ac
Σ
Sigma: summation / sum of all values in range of series
ΣΣ
Double sigma: double summation
∏
Capital pi: product / product of all values in range of series
e
Constant e / Euler's number: e = 2.718281828...
γ
Euler-Mascheroni constant: γ = 0.5772156649...
φ
Golden ratio constant
LINEAR ALGEBRA SYMBOLS
·
Dot: scalar product
×
Cross: vector product
A⊗B
Tensor product: tensor product of A and B
[ ]
Brackets: matrix of numbers
( )
Parentheses: matrix of numbers
| A |
Determinant: determinant of matrix A
det(A)
Determinant: determinant of matrix A
|| x ||
Double vertical bars: norm
AT
Transpose: matrix transpose
A†
Hermitian matrix: matrix conjugate transpose
A*
Hermitian matrix: matrix conjugate transpose
A-1
Inverse matrix: A A-1 = I
rank(A)
Matrix rank: rank of matrix A
dim(U)
Dimension: dimension of matrix A
STATISTICS SYMBOLS
P(A)
Probability function: probability of event A
P(A ⋂ B)
Probability of events intersection: probability of events A and B
P(A ⋃ B)
Probability of events union: probability of events A or B
P(A | B)
Conditional probability function: probability of event A given event B occured
f(x)
Probability density function (pdf): P(a ≤ x ≤ b) = ∫ f(x) dx
F(x)
Cumulative distribution function (cdf): F(x) = P(X ≤ x)
μ
Population mean: mean of population values
E(X)
Expectation value: expected value of random variable X
E(X | Y)
Conditional expectation: expected value of random variable X given Y
var(X)
Variance: variance of random variable X
σ2
Variance: variance of population values
std(X)
Standard deviation: standard deviation of random variable X
σX
Standard deviation: standard deviation of random variable X
cov(X,Y)
Covariance: covariance of random variables X and Y
corr(X,Y)
Correlation: correlation of random variables X and Y
ρX,Y
Correlation: correlation of random variables X and Y
∑
Summation: sum of all values in range of series
∑∑
Double summation
Mo
Mode: value that occurs most frequently in population
MR
Mid-range: MR = (xmax+xmin)/2
Md
Sample median: half the population is below this value
Q1
Lower / first quartile: 25% of population are below this value
Q2
Median / second quartile: 50% of population are below this value = median of samples
Q3
Upper / third quartile: 75% of population are below this value
x
Sample mean: average / arithmetic mean
s2
Sample variance: population samples variance estimator
s
Sample standard deviation: population samples standard deviation estimator
zx
Standard score: zx = (x-x) / sx
X~
Distribution of X: distribution of random variable X
N(μ,σ2)
Normal distribution: gaussian distribution
U(a,b)
Uniform distribution: equal probability in range a,b
exp(λ)
Exponential distribution: f(x) = λe-λx , x ≥ 0
gamma(c,λ)
Gamma distribution: f(x) = λcxc-1e-λx / Γ(c), x ≥ 0
χ2(k)
Chi-square distribution: f(x) = xk/2-1e-x/2 / (2k/2 Γ(k/2))
F(k1, k2)
F distribution
Bin(n,p)
Binomial distribution: f(k) = nCk pk(1-p)n-k
Poisson(λ)
Poisson distribution: f(k) = λke-λ / k!
Geom(p)
Geometric distribution: f(k) = p(1-p)k
HG(N,K,n)
Hyper-geometric distribution
Bern(p)
Bernoulli distribution
COMBINATORICS SYMBOLS
n!
Factorial - n! = 1⋅2⋅3⋅...⋅n
nPk
Permutation: nPk = n! / (n-k)!
nCk
Combination: nCk = n! / k!(n-k)!
SET THEORY SYMBOLS
{ }
Set: a collection of elements
A ∩ B
Intersection: objects that belong to set A and set B
A ∪ B
Union: objects that belong to set A or set B
A ⊆ B
Subset: A is a subset of B; set A is included in set B
A ⊂ B
Proper subset / strict subset: set A is a subset of set B, and set A is not equal to set B
A ⊄ B
Not subset: set A is not a subset of set B
A ⊇ B
Superset: A is a superset of B; set A includes set B
A ⊃ B
Proper superset / strict superset: A is a superset of B, and A is not equal to B
A ⊅ B
Not superset: set A is not a superset of set B
A ⊅ B
Not superset: set A is not a superset of set B
2A
Power set: all subsets of A
P(A)
Power set: all subsets of A
A = B
Equality: both sets have the same members
Ac
Complement: all the objects that do not belong to set A
A \ B
Relative complement: objects that belong to A and not to B
A - B
Relative complement: objects that belong to A and not to B
A ∆ B
Symmetric difference: objects that belong to A or B but not to their intersection
A ⊖ B
Symmetric difference: objects that belong to A or B but not to their intersection
a ∈ A
Element of, belongs to: set membership
x ∉ A
Not element of: no set membership
(a,b)
Ordered pair: collection of 2 elements
A×B
Cartesian product: set of all ordered pairs from A and B
|A|
Cardinality: the number of elements of set A
#A
Cardinality: the number of elements of set A
|
Vertical bar: such that
N0
Aleph-null: infinite cardinality of natural numbers set
N1
Aleph-one: cardinality of countable ordinal numbers set
Ø
Empty set: Ø = { }
U
Universal set: set of all possible values
ℕ0
Natural numbers with zero: ℕ0 = {0, 1, 2, 3, 4,...}
ℕ1
Natural numbers without zero: ℕ1 = {1, 2, 3, 4, 5,...}
ℕ*
Natural numbers without zero: ℕ* = {1, 2, 3, 4, 5,...}
ℤ
Integer numbers: ℤ = {...-3, -2, -1, 0, 1, 2, 3,...}
ℚ
Rational numbers: ℚ = {x | x = a/b, a,b ∈ ℤ}
ℝ
Real numbers: ℝ = {x | -∞ < x < +∞}
ℝ
Extended real numbers: ℝ = {x | -∞ ≤ x ≤ +∞}, ℝ = ℝ ∪ {-∞,+∞}
ℂ
Complex numbers: ℂ = {z | z = a+bi, -∞ < a < +∞, -∞ < b < +∞}
LOGIC SYMBOLS
⋅
And
^
Caret / circumflex: and
∧
Caret: and
&
Ampersand: and
+
Plus: or
∨
Reversed caret: or
|
Vertical line: or
x'
Single quote: not / negation
x
Bar: not / negation
¬
Not / negation
!
Exclamation mark: not / negation
⊕
Circled plus / oplus: exclusive or / xor
~
Tilde: negation
⇒
Implies
⇔
Equivalent: if and only if (iff)
↔
Equivalent: if and only if (iff)
∀
For all
∃
There exists
∃!
There exists one and only one
∄
There does not exist
∴
Therefore
∵
Because / since
∵
Because / since
CALCULUS & ANALYSIS SYMBOLS
limx→af(x)
Limit value of a function
ε
Epsilon: represents a very small number, near zero
y'
Derivative: Lagrange's notation
y''
Second derivative: derivative of derivative
y''
Second derivative: derivative of derivative
y(n)
Nth derivative: n times derivation
dy
——
dx
Derivative: Leibniz's notation
d2y
——
dx2
Derivative: Leibniz's notation
dny
——
dxn
Nth derivative: n times derivation
Dxy
Derivative: Euler's notation
Dx2y
Second derivative: derivative of derivative
∂f(x,y)
———
∂x
Partial derivative
∫
Integral: opposite to derivation
∫∫
Double integral: integration of function of 2 variables
∫∫∫
Triple integral: integration of function of 3 variables
∮
Closed contour / line integral
∯
Closed surface integral
∰
Closed volume integral
i
Imaginary unit: i ≡ √-1
z*
Complex conjugate: z = a+bi → z* = a-bi
z
Complex conjugate: z = a+bi → z = a-bi
Re(z)
Real part of a complex number: z = a+bi → Re(z) = a
Im(z)
Imaginary part of a complex number: z = a+bi → Im(z) = b
| z |
Absolute value / modulus / magnitude of a complex number: |z| = |a+bi| = √(a2+b2)
arg(z)
Argument of a complex number: the angle of the radius in the complex plane
∇
Nabla / del: gradient / divergence operator
x * y
Convolution: y(t) = x(t) * h(t)
δ
Delta function
GREEK ALPHABET LETTERS
Α - α - Alpha
Β - β - Beta
Γ - γ - Gamma
Δ - δ - Delta
Ε - ε - Epsilon
Ζ - ζ - Zeta
Η - η - Eta
Θ - θ - Theta
Ι - ι - Iota
Κ - κ - Kappa
Λ - λ - Lambda
Μ - μ - Mu
Ν - ν - Nu
Ξ - ξ - Xi
Ο - ο - Omicron
Π - π - Pi
Ρ - ρ - Rho
Σ - σ - Sigma
Τ - τ - Tau
Υ - υ - Upsilon
Φ - φ - Phi
Χ - χ - Chi
Ψ - ψ - Psi
Ω - ω - Omega
OTHER SYMBOLS
→
Rightwards arrow: limx→a
←
Leftwards arrow
↔
Left-rigt arrow: exchange of elements
↦
Rightwards arrow from bar: associate
|
Vertical bar: such that
:
Colon: such that
~
Tilde: asymptotically equal
≡
Triple bar: coincident
≈
Squiggly equal: approximately equal
∨ = | = OR = ∪ = union
∧ = & = AND = ∩ = intersection